Internal combustion engine



y 7, 1966 N. E. FARB 3,251,347

INTERNAL COMBUSTION ENGINE Filed Nov. 26, 1963 3 Sheets-Sheet l I N VE NTOR. Wa /144w 425 May 17, 1966 N. E. FARB INTERNAL COMBUSTION ENGINE 3Sheets-Sheet 2 -&

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United States Patent 3,251,347 INTERNAL COMBUSTION ENGINE Norman E.Farb, 2106 Denise Ave., Orange, Calif. Filed Nov. 26, 1963, Ser. No.325,899 13 Claims. '(Cl. 12311) This invention provides an improvedinternal combustion engine with a high compression ratio and hightorque,

and a minimum number of main moving parts.

Briefly, the invention includes first and second annular bodies securedtogether so the two bodies make a sliding fit with each other and forman annular assembly in which the two bodies are rotatable with respectto each other about a common axis. The bodies each have opposed annularrecesses opening into each other to form an annular working volume inthe assembly. At least two separate pistons are secured to each body inits recess, and each piston is of substantially the same cross sectionalshape and size as the working volume. Means are provided for introducingand burning a fuel mixture in the working volume between the pistons toforce them apart and cause the bodies to rotate with respect to eachother. Means are also provided for restraining the bodies from moving inone direction about the common axis and leaving them free to move in theother.

In the preferred form of the invention, each body is hemitoroidal inshape, and an annualr slide valve is sandwiched between the two bodiesand adjacent the working volume. The slide valve includes inlet andexhaust ports for admitting a combustible fuel mixture into the workingvolume and for exhausting burned fuel from the working volume, Theannular bodies are held together in sliding relationship at their innerand outer respective edges by clamp means, and ratchet means areprovided for alternately limiting the movement of the bodies withrespect to one of the set of clamp rings while the bodies sequentiallyengage and drive the other set of clamp rings. Preferably, a pluralityof pistons are mounted on each body to give the engine multi-cylinderperformance, and the pistons are hollow and vented for internal cooling.Cooling fins are also secured to the assembly to prevent overheating.Preferably, the fins extend radially so that bolts 29. A pair ofdiametrically opposed mounting cars on the first and second outer clamprings include collinear bores 31 for mounting the engine on a frame (notshown). I

A pair of radially extending'and diametrically opposed inlet ports 32 inthe annular slide valve ring periodically connects the working volume ofthe engine between adjacent pistons with radially extending and radiallyspaced intake channels 33 which open through the first clamp ring andare each connected to an intake manifold 34 which is suppliedcombustible gaseous fuel from a carburetor (not shown) which may be ofconventional type.

A pair of radially extending and diametrically opposed exhaust ports 36located in the valve ring between adjacent inlet ports periodicallyconnect the working volume of the engine between adjacent pistons withradially extending and radially spaced exhaust channels 38 which openthrough the second outer clamp ring into an exhaust manifold 40 as thevalve ring moves with respect to the hemi-toroid bodies. First andsecond annular gaskets 42, 44, respectively, of approximately squarecross section each make a sliding fit against the outer portion of eachpiston and against the upper and lower (as viewed in FIG. 2) edges ofthe interior portion of the annular slide valve. A separate outwardlyextending tab 46 on a separate semicircular piston sealing ring 47 oneach end of each piston fits between the first and second outer gasketsto i prevent gas by-passing the pistons.

air is driven centrifugally outwardly across opposite faces of theengine.

These and other aspects of the invention will be more fully understoodfrom the following detailed description and the accompanying drawings,in which:

FIG. l is a schematic plan view, partly broken away of the presentlypreferred embodiment of the invention;

FIG. 2 is a view taken on line 2-2 of FIG. 1; and

FIG. 3 is an enlarged view taken in the vicinity of line 33 of FIG. 1..

Referring to FIGS. 1 and '2, an upper or first hemitoroid body 10 restson a lower or second hemi-toroid body 12. The two bodies each includeopposing annular concave surfaces 14 which fit together to form atoroidal working volume 16. Four first pistons 18A, 18B, 18C, and 18D,are formed at equal angles integrally with the in- 'ten'or surface ofthe first body. Each piston is in the form of a toroid segment and ofsuch size to substantially fill the working volume formed between thetwo bodies. Four second pistons 20A, 20B, 20C, and 20D, identical withthe first pistons, are formed integrally with the second body, andarranged so that a piston in one set fits between adjacent pistons inthe other set,

An annular slide valve ring 22 is sandwiched to make a sliding fitbetween an outer flange 24 on the first body and an outer flange 25 onthe second body. The outer flanges on the first and second bodies areheld together in a sliding relationship by first and second outerannular clamp rings 26, 27, respectively, held together by nuts 28 and Afirst forward ratchet pawl 48 is mounted on a pivot pin 49 in aninwardly opening recess 50 in the first outer clamp ring and is urged bya compression spring 51 out of the recess and into engagement with anouter annular ring gear 53 on the first hemi-toroid body. A cable 52 isattached to the pawl 48 so the pawl can be pulled into the recess andout of engagement with ring gear 53. As shown best in FIG. 1, theforward ratchet pawl is urged outwardly to engage the teeth in the outerring gear on the first hemi-toroid body so that the body can rotate onlyin a clockwise direction, as viewed in FIG. 1. A second forward ratchetpawl 54 (FIG. 2) is mounted by a pivot pin 55 in an inwardly openingrecess 56 in the second outer clamp ring (FIG. 2), and is urged by aspring (not shown for simplicity) to move into or out of engagement withan annular outer ring gear 58 on the second hemitoroid body. The secondforward ratchet pawl is also connected to a cable and is set exactly asthe first forward ratchet pawl so that the second hemi-toroid body canmove only in a clockwise direction, as viewed in FIGS. 1 and 3. A firstreversing ratchet pawl 60 is mounted by a pivot pin 61 in a recess 62 inthe first outer clamp ring and is urged by a compression spring 63 tomove into engagement with the teeth in the outer ring gear on the firsthemitoroid body. A cable 63A is attached to pawl 60 for controlling itsposition. An identical second reversing ratchet pawl 64 (FIG. 2) issimilarly mounted in the second outer clamp ring, and also actuated by arespective cable (not shown) to engage or not engage the teeth of theouter annular ring gear on the second hemi-toroid body. Conveniently,the cables attached to the forward pawls are actuated by a forwardsolenoid (not shown) and the cables attached to the reverse pawls areactuated by a reverse solenoid (not shown). By de-energizing the forwardand reverse solenoids, the pawls are set so that the hemi-toro'id bodiescan rotate only in the clockwise direction (as viewed in FIGS. 1 and 3).Energizing the forward and reverse ratchet solenoids permits thehemi-toroid bodies to rotate only in the counterclockwise direction whenthe engine is to be driven in a reverse direction. If desired, more thanone set of first and second forward and reversing ratchets can be usedaround the peripheries of the first and second outer clamp rings.

The first and second hemi-toroid bodies include inner flanges 66, 67,respectively, which are clamped together in sliding relationship betweena first inner clamp ring 68 and a second inner clamp ring 70 heldtogether by nuts 72 and bolts 74 to sandwich between them a rotatablefly wheel 76 which is secured by a key 78 to drive a rotatable powershaft 80 that passes coaxially through the annular bodies. A pair ofdiametrically opposed and outwardly extending bevel drive gears 82 areeach journalled in the periphery of the fly wheel and engage a firstinner annular bevel ring gear 84 and a second annular bevel ring gear 86on the first and second hemi-toroid bodies, respectively. An annularinner gasket 88 makes a sliding seal between the outer portions of theinner flanges on the first and second hemi-toroid bodies.

Each of the four first pistons carries an inner valve shaft 90journalled through its inner side wall. An inner valve spur gear 92 onthe inner end of the inner valve shaft 90 rides in an annular secondinner ring spur gear 94 on the inner (upper, as viewed in FIG. 2) faceof the inner flange on the second hemi-toroid body. The outer end of theinner valve shaft 90 is connected through a valve ratchet assembly 96 toa first intermediate spur gear 98 (FIG. 3) which engages a secondintermediate spur gear 100 rigidly connected to the inner end of aradially extending outer valve shaft 102 journalled through the outerside wall of the piston and carrying an outer spur valve gear 104 whichrides in an annular first outer ring spur gear 106 on the top (as viewedin FIG. 2) face of the annular slide valve.

As shown best in FIGS, each valve ratchet 96 includes a first disk 1G8rigidly secured to the outer end of the inner valve shaft 90. Outwardlyfacing serrations 109 engage inner facing serrations 110 on a seconddisk 111 secured to a sleeve 112 which makes a sliding fit on a splinedstub shaft 114 secured to the first intermediate gear 98 and journalledin a support block 116. The second disk is urged toward the first by acompression spring 118 coaxially disposed around the sleeve 112 betweenthe first disk and the first intermediate valve gear 98. Each piston inthe second set carries a valve gear and ratchet arrangement identicalwith that just described with respect to the first pistons, and likereference numbers are used to identify corresponding elements. However,each inner valve spur gear 2 on the pistons in the second set ride on anannular first inner ring spur gear 119 on the inner (lower as viewed inFIG. 2) face of the inner flange on the first hemi-toroid body, and theouter spur valve gear 104 rides in an annular second outer ring spurgear 120 on the bottom (as viewed in FIG. 2) face of the annular slidevalve.

For the second set of pistons, i.e., those formed integrally with thesecond hemi-toroid body, the serrations in the disks 108 and 111 arearranged so that the serrations engage when the first disk is rotated ina clockwise direction looking radially outwardly, and slip when the diskis rotated in the opposite direction. The reverse is true for the valvedisks in the pistons in the first set. Thus, as the hemi-toroid bodiesrotate relative to each other, the slide valve ring is driven throughthe valve gears to open and close inlet and exhaust channels in thefirst and second outer clamp rings as required for engine operationdescribed below.

As shown best in FIG. '1, the annular first and second outer ring spurgears 106, 120 on the slide valve each has four short interrupted spaces107, 121, respectively, spaced 90 apart around the slide valve. The gapsinsure proper synchronization of the slide valve with the pistons duringengine operation so that when adjacent pistons are closest together forthe completion of a compression or exhaust stroke, the leading pistoncovers an adjacent intake port and the trailing piston covers anadjacent exhaust port.

i A plurality of radially extending cooling fins 122 are secured to thefirst and second clamp rings, and radially extending arcuate fins 124are secured to the first and second hemi-toroid bodies. Thus, as thebodies rotate, the fins not only radiate heat, but also force air toflow radially outwardly by centrifugal force. Inwardly facing scoops 126direct some of the air flow through piston vents 128 in the side wallsof the hemi-toroid bodies to force cooling air through the interior ofthe pistons, thus providing internal cooling pistons.

In operating the engine, say, in a forward direction, the forward andreverse ratchet pawls are set as shown in FIG. 1 so the hemi-toroidbodies can each rotate in a clockwise (as viewed in FIG. 2) direction. Acombustible gaseous'mixture of fuel and air is supplied through thecarburetor intake, and the engine is cranked by a suitable crank, or byinjecting the fuel mixture under sufficient pressure so as to drive theengine like a compressor until it develops sufiicient speed andcompression to ignite the fuel by diesel-type combustion. Assuming thatthere are four pistons connected to each hemi-toroid body (of course,any desired number may be used), the engine functions in a typicalfour-cycle fashion with the cycles being arranged in the order ofintake, compression, power, and exhaust in the clockwise direction asviewed in FIG. 1. Thus, with the eight pistons shown in FIG. 1, thereare two of each of the cycles taking place at one time. For example,assume that the fuel mixture between pistons 18A and 20A has beencompressed sufficiently to cause combustion, which forces the pistonsapart. The second hemi-toroid body is prevented from moving in acounterclockwise direction by the second forward ratchet. Therefore, theexpanding gas forces the piston 18A connected to the first hemi-toroidbody in a clockwise direction. The first hemi-toroid body is free tomove in this direction because of the arrangement of the forward ratchetpawl. The gas in the space between pistons 18A and 20B is exhaustedthrough exhaust port 36A in the slide valve as the first hemi-toroidbody moves in the clockwise direction. The space between pistons 20B and18B fills with combustible gas through intake port 32B in the slidevalve ring during an intake cycle, and the gas in the space betweenpistons 18B and 20C undergoes compression. The same analysis can becarried entirely around the engine, but is not repeated for brevity. Aspiston 18B on the first hemi-toroid body approaches piston 200 on thesecond hemi-toroid body, the pressure between the two pistons risesrapidly until the ignition temperature is reached. The first hemi-toroidbody is now prevented from moving backward or in a counterclockwisedirection by its forward ratchet pawl, but the second hemi-toroid bodyis free to move forward as piston 20C is pushed away from piston 188 bythe expanding, burning gas, and the cycle is repeated. Of course,conventional spark plug ignition may be used instead of relying ondiesel combustion, and an annular reversible conventional Sprague clutchtype of ratchet mechanism can be used on the outer clamp rings to engagethe herni-toroid bodies, instead of the tooth and pawl arrangement shownin the drawings.

As each hemi-toroid body advances, its respective bevel ring gearengages the bevel drive gears on the fly wheel and carries the fly wheelaround at a rate equal to one-half of that of the hemi-toroid bodies,thereby providing an automatic gear reduction. At the same time, thevalve gears are driven by the respective inner annular ring spur gearson the inner flanges of the hemi-toroid bodies and thereby drive thevalve ring around in counterclockwise direction (as viewed in FIG. 1)with respect to the hemitoroidal bodies and the first and second outerclamp rings to open and close the intake and exhaust channels asrequired for proper intake, compression, power, and exhaust cycles.

An important advantage of the engine is that the exhaust and valve portsin the valve ring are blocked off from the working volume by the pistonsduring the compression and power strokes, and therefore are notsubjected to the usual high temperatures and high pressures encounteredby valves in conventional engines.

Since no crank shafts, or the like, are used, the pistons approach eachother at a high rate of speed with a minimum dwell time, thus makingpossible high compression ratios not previously obtainable withconventional reciprocating piston engines. A high torque is producedbecause the pistons are at a relatively great average distance from thedrive shaft all of the time, particularly during the beginning of apower stroke. The integral formation of each piston around substantiallyone-half of its transverse cross sectional area with a respectivehemi-toroid body reduces sealing problems and improves engineefficiency. Finally, the vented hollow pistons provide for internalcooling to increase further engine efiiciency.

I claim:

1. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, means for introducing and burninga fuel mixture in the working volume between 'the pistons to force themapart and cause the bodies to rotate with respect to each other, andmeans for restraining the bodies from moving in one direction andleaving them free to move in the other.

2. An internal combustion engine comprising first and second hemi-toroidbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed hemi-toroid recesses opening into each otherto form a toroid working volume in the assembly, at least two separatepistons secured to each body in its recess, each piston being ofsubstantially the same cross sectional shape and size as the workingvolume, means for introducing and burning a fuel mixture in the workingvolume between the pistons to force them apart and cause the bodies torotate with respect to each other, and means for restraining the bodiesfrom moving in one direction and leaving them free to move in the other.

3. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, an annular slide valve disposedbetween the two bodies and having port means the bodies to rotate withrespect to each other, and meansfor restraining the bodies from movingin one direction and leaving them free to move in the other.

4. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, an annular slide valve disposedbetween the two bodies and having port means for introducing acombustible fuel mixture in the working volume between the pistons toforce them apart and cause the bodies to rotate with respect to eachother, gear means on the slide valve, gear means carried by the bodiesto engage the gear means on the slide valve and rotate it with respectto the bodies as the bodies rotate with respect to each other, and meansfor restraining the bodies from moving in one direction and leaving themfree to move in the Other.

5. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly inwhich the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, means for introducing and burninga fuel mixture in the working volume between the pistons to force themapart and cause the bodies to rotate with respect to each other, meansfor restraining the bodies from moving in one direction and leaving themfree to move in the other, and radially extending cooling fins on thebodies for radiaating heat and centrifugally driving cooling air acrossthe bodies. 7

6. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, a plurality of separate pistons secured to each body in itsrecess, each piston on one body being disposed between adjacent pistonson the other body, the pistons being of substantially the same crosssectional shape and size as the working volume, means for introducingand burning a fuel mixture in the working volume between the pistons toforce them apart and cause the bodies to rotate with respect to eachother, and means for restraining the bodies from moving in one directionand leaving them free to move in the other.

7. An internal combustion engine comprising first and second annularbodies, outer and inner clamping means for securing the outer and innerrespective peripheries of the two bodies together to make a sliding sealfit with respect to each other and a sliding fit with respect to theouter and inner clamping means, the bodies forming an annular assemblyin which the two bodies are rotat able with respect to each other abouta common axis,

the bodies each having opposed annular recesses opening into each otherin the direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, means for introducing and burninga fuel mixture in the working volume between the pistons to force themapart and cause the bodies to rotate with respect to each other, andmeans for restraining the bodies from moving in one direction withrespect to one of the clamping means and leaving them free to move inthe. other direction.

8. An internal combustion engine comprising first and second annularbodies, outer and inner clamping means for securing the outer and innerrespective peripheries of the two bodies together to make a sliding sealfit with respect to each other and a sliding fit with respect to theouter and inner clamping means, the bodies forming an annular assemblyin which the two bodies are rotatable with respect to each other about acommon axis, the bodies each having opposed annular recesses openinginto each other in the direction of said axis to form an annular workingvolume in the assembly, at least two separate pistons secured to eachbody in its recess, each piston being of substantially the same crosssectional shape and size as the working volume, means for introducingand burning a fuel mixture in the working volume between the pistons .toforce them apart and cause the bodies to rotate with respect to eachother, and ratchet means for restraining the bodies from moving in onedirection with respect to one of the clamping means and leaving themfree to move in the other direction.

9. An internal combustion engine comprising first and second annularbodies, outer and inner clamping means for securing the outer and innerrespective peripheries of the two bodies together to make a sliding sealfit with respect to each other and a sliding fit with respect to theouter and inner clamping means, the bodies forming an annular assemblyin which the two bodies are rotatable with respect to each other about acommon axis, the bodies each having opposed annular recess opening intoeach other in the direction of said axis to form an annular workingvolume in the assembly, at-least two separate pistons secured to eachbody in its recess, each piston being of substantially the same crosssectional shape and size as the working volume, means for introducingand burning a fuel mixture in the working volume between the pistons toforce them apart and cause the bodies to rotate with respect to eachother, and reversible ratchet means for restraining the bodies frommoving in one direction with respect to one of the clamping means andleaving them free to move in the other direction.

10. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, means for intro ducing and burninga fuel mixture in the working volume between the pistons to force themapart and cause the bodies to rotate with respect to each other, meansfor restraining the bodies from moving in one direction and leaving themfree to move in the other, a power output shaft disposed adjacent thebodies, and means for coupling the relative movement of the bodies tothe shaft.

11. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume, the pistons being hollow, meansforming a passageway for a cooling medium through the pistons, means forintroducing and burning a fuel mixture in the working volume between thepistons to force them apart and cause the bodies to rotate with respectto each other, and means for restraining the bodies from moving in onedirection and leaving them free to move in the other direction.

12. An internal combustion engine comprising first and second annularbodies, means for securing the two bodies together to make a slidingseal fit with each other and form an annular assembly in which the twobodies are rotatable with respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume to make a sliding fit therein, aseparate piston ring disposed around each piston where it makes .asliding fit in the working volume, means for introducing and burning afuel mixture in the working volume between the pistons to force themapart and cause the bodies to rotate with respect to each other, andmeans for restraining the bodies from moving in one direction andleaving them free to move in the other direction.

13. An internal combustion engine comprising first and second annularbodies, an annular valve ring disposed between them, means for securingthe two bodies together to make a sliding seal fit against oppositesides of the valve ring and form an annular assembly in which the twobodies are rotatable wtih respect to each other about a common axis, thebodies each having opposed annular recesses opening into each other inthe direction of said axis to form an annular working volume in theassembly, at least two separate pistons secured to each body in itsrecess, each piston being of substantially the same cross sectionalshape and size as the working volume to make a sliding fit therein, thevalve ring having ports opening through it for introducing and burning afuel mixture in the working volume between the pistons to force themapart and cause the bodies to rotate with respect to each other, a pairof annular spaced gaskets disposed between the pistons and the valvering and on opposite sides of the ports in the valve ring, a separatesealing ring disposed around each end of each piston where it makes asliding fit in the working volume, and a separate tab on each ringextending between the two gaskets, and means for restraining the bodiesfrom moving in one direction and leaving them free to move in the otherdirection.

References Cited by the Examiner UNITED STATES PATENTS 797,093 8/ 1905Bellah 9l6.0

915,296 3/ 1909 Holloway 91--60 1,024,166 4/1912 Weed 12 3-.11 1,370,2983/ 1921 Fischer :123-11 1,921,747 8/ 1933 Greve 103-429 FOREIGN PATENTS976,094 '10/ 1950 France. 1,277,381 10/1961 France.

419,730 4/ 1947 Italy.

SAMUEL LEVINE, Primary Examiner.

DONLEY J. STOCKING, Examiner.

R. M. VARGO, Assistant Examiner.

1. AN INTERNAL COMBUSTION ENGINE COMPRISING FIRST AND SECOND ANNULARBODIES, MEANS FOR SECURING THE TWO BODIES TOGETHER TO MAKE A SLIDINGSEAL FIT WITH EACH OTHER AND FORM AN ANNULAR ASSEMBLY IN WHICH THE TWOBODIES ARE ROTATABLE WITH RESPECT TO EACH OTHER ABOUT A COMMON AXIS, THEBODIES EACH HAVING OPPOSED ANNULAR RECESSES OPENING INTO EACH OTHER INTHE DIRECTION OF SAID AXIS TO FORM AN ANNULAR WORKING VOLUME IN THEASSEMBLY, AT LEAST TWO SEPARATE PISTONS SECURED TO EACH BODY IN ITSRECESS, EACH PISTON BEING OF SUBSTANTIALLY THE SAME CROSS SECTIONALSHAPE AND SIZE AS THE WORKING VOLUME, MEANS FOR INTRODUCING AND BURNINGA FUEL MIXTURE IN THE WORKING VOLUME BETWEEN